Fuel burner



Aug. 2, 1932. w. F. KEENAN. JR

FUEL BURNER Filed Dec. 7. 1927 ATTORNEY Patented Aug .2, 1932 UNITED STATES PATENT OFFICE WALTER F. KEJENAN, J'R., F PELHAM, NEW YORK, ASSIGNOR 'I'O FOSTER-WHEELER CORPORATION, OF NEW YORK, N. Y., .A. CORPORATION OF NEW YORK FUEL BURNER,

Application filed December 7, 1927. Serial No. 2383M.

The present invention relates to furnaces wherein a combustible mixture of air and comminuted fuel is discharged into the furnace' chamber under pressure and burned in suspension. The object of my present invention is to provide improved apparatus for directing and regulating the flow of the stream of combustible material into the furinvention are to provide improved means for regulating the rate of discharge of the combustible mixture and for regulating and directing the flow of secondary air to different portions of the'stream of combustible material.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, and the advantages possessed by it reference should be had to the accompanying drawing and descriptive matter in which I have illustrated and described 'a preferred embodiment of the invention. I

Of the drawing: 1

Fig. 1 is an elevation partly in section 0 a preferred embodiment of my invention;

Fig. 2 is a. sectionon the line 22 of Fig. 1;

Fig. 3 is a section taken on the line 3-3 of Fig. 1; and I Fig. 4 is a section taken on the line 44 of Fig. 1.

In the drawing I have illustrated a preferred embodiment of my improved pulverized fuel burner mounted in an opening A in a wall of a furnace A. The burner apparatus comprises a thimble casing B substantially cylindrical in form and arranged with its inner end fitting into the outer portion of the wallopening A and secured to the outer face of the wall by a flange B welded to the outer surface of the casing.

A hollow truncated burner cone or frustoconical burner member C is arranged with its smaller end portion projecting into the opening A and extending slightly beyond the inner end of the casing B. Theburner cone is secured to the casing B by a flange C mounted on an intermediate portion of the cone and connected to a flange B on the outer end of casing B. The inner endof the cone is formed by a detachable burner tip C secured to the remaining portion of the cone by a tapered sleeve U A cylindrical sleeve casing D is arranged within the outer portion of the cone G and supported therefrom by a series of radial bolts D, each of which has its outer threaded end passing through the cone member and secured thereto by a nut. The sleeve casing is closed at its outer end by a circular plate D having an opening D at the center thereof. The outer end portion of the casing is formed with a pair of diametrically opposite rectangular openings D therein.

A cylindrical nozzle sleeve Econcentric with and slightly less diameter than the casing D is slidably mounted within the casing D. The sleeve -E is provided at its inner end with a tapered nozzle tip E having its larger end detachably secured to the end of the sleeve. At diametrically opposite points at its outer end, the sleeve is provided with recessed portions E of substantially the same size and arranged to normally register with the-openings D A spider E is mounted in and secured to the .sleeve at a point adjacent the bottom of the in the burner casing.

recesses E and arranged with its legs forming a circular opening E, withinwhich is secured a circular nut E having a threaded opening E.

A threaded shaft F is mounted within the casing D and formed with an outer unthreaded portion F passing through the opening D in the end plate D and with an intermediate portion threaded through the nut E. Secured to the outer end of the shaft F is a hand wheel F having its hub member abutting the outer face of the end plate D The to vary the position of the nozzle tip E rela-' tive to the cone C and particularly with respect to the cone tip C The fuel burner construction heretofore described is provided with means for passing comminuted fuel into the mixing chamber formed by the outer wall of theburner casing and the inner wall of the cone. In

the present embodiment anvinlet casin G of:

involute or spiral form is arranged to eliver a mixture of fuel and air to the mixing chamber. The inlet casing wall is connected by an annular flange Gr to an annular flange C mounted on the outer end of the burner cone. As shown in Fig. 3, the casing is constructed with a spiral passage G connected at its outer end to a supply of pulverized fuel and arranged to discharge to the mixing chamber through an annular discharge opening G The casing G is mounted on the casing D with the inner wall of the casing passage G contac-ting with the cylindrical surface of the casing. The passage extends about the easing D and progressively decreases in width, measured axially of the burner, to provide a tapering cross section in the direction of flow and thereby provide a uniform velocity of flow of combustible mixture through the discharge opening G.

In the operation of the apparatus shown, a mixture of powdered fuel and air is su plied to the passage G. The shape of t e passage forces the mixture of air and fuel to pass in a spiral path winding about the axis of the burner structure and discharging from the opening G with a whirling motion about the casing D. The whirling mixture passes through the cone tip section 0 into the furnace chamber, where it rapidly increases in area due to its centrifugal force.

Where the air carryin the comminuted fuel into the furnace cham er is not sufiicient to support complete combustion of fuel, I'

- have provided air inlet means through which secondary air can be admitted in regulable amounts into different portions of the spiral stream of air and fuel from the outlet G. In the construction shown, I have provided the outer portion of the casing D with a cylindrical damped sleeve H having openings H therein corresponding in size and shape with the openings D and recesses E The sleeve H is provided with a handle H, by which it can berotated on the casing D to vary the size of the opening formed by the corresponding openings D and H. Air is drawn spaced points around its circumference with rectangularly shaped openings B. Mounted on that portion of the thimble member is a cylindrical damper sleeve J having its main portion concentric with and of slightly larger diameter than the reduced portion of the thimble member B. The side portions of the damper J are formed by circular guide rings J rotatably mounted on the thimble casing B. As shown in Fig. 4: the damper is arranged with openings J 2 therein of approximatel the size and-shape of the openings B. he damper J is rotated by means of handles J secured to the circumference thereof at spaced points to vary the size of air inlet openings formed by the apertures B and J In the operation of my improved apparatus, a stream of air under pressure carr ing a quantity of finely pulverized fuel suc as powdered coal enters the inlet end of the inlet casing G and passes in a spiral path through the annular discharge outlet G? into the mixing chamber. The whirling motion given to the coal and air by the form of the casing chamber G causes the mixture to pass in a spiral path through the burner cone to the furnace chamber. When the amount of air entering the chamber G is not sufficient for complete combustion of the fuel, the sleeve damper H is rotated to permit a stream of air to be drawn through the nozzle E and mix with the primary air and fuel in the outer portion of the cone. If a greater amount of secondary air is required than can beobtained with the damper H in its wide open position, or if it is desirable to also permit secondary air to enter around the main stream of coal and air when the damper H is partly open, the damper J is moved to permit a stream of air to pass around the outer portion of the burner cone and to mix with to the discharge end of thecone is varied,

' the main stream of combustible mixture at a chamber. The discharge velocity is especial- III 1y important as upon that factor depends the length of the flame rojected into the furnace.

It has been found .t at too close a flame tends to burn up the tip of the burner cone and nozzle. For that reason, I have provided detachable burner and nozzle tip sections so that those sections may be replaced by similar or differently shaped sections .when necessary. While I have described the burner as arranged in the side wall of the furnace, my invention may be installed as well in a horizontal or inclined position in any of the other furnace walls,

My invention is characterized by the simplicity of construction of the various parts and the ease and efiectiveness of the regulation of the fuel and air supply. lhe involute shaped inlet passage isespecially advantageous in providing a uniform mixture of fuel and air for combustion,

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed Without departing from the spirit of my invention as set forth in the appended claims and that in some cases certain features of my invention may be used to advange without a corresponding use of other features.

Having now described my invention, What I claim as new and desire to secure by Letiers Patent, is

l. A comminuted fuel burner ada ted to be mounted in an opening in a wall 0 a furnace chamber comprising a hollow frusto conical burner member adapted to extend into said wall opening, an inlet casing having a chamber of involute form secured to and arranged to discharge a combustible mixture into said burner member, a cylindrical cas-' ing mounted in said burner member, a nozzle sleeve movable within said cylindrical casing, a nozzle tip on the inner end of said sleeve, means for axially moving said sleeve,

a regulable opening for admitting air through said sleeve and a regulable opening for admitting air around the inner end of said burner member.

2. A comminuted fuel burner comprising an outer casing adapted to be mounted in a furnace wall opening, a frusto-conical burner member mounted in said outer casing and having its inner portion spaced from the walls of said casing to provide an annular passage therebetween, an axially adjustable nozzle member positioned within said burner member and spaced from the inner wall thereof to provide a second annular passage therebetween, a comminuted' fuel and air inlet regulating the velocity of the commember mounted in said outer casing and having its inner portion spaced from the" walls of said casing to provide an annular passage therebetween, an axially ad'ustable nozzle member positioned within sai burner member and spaced from the inner wall thereof to provide a second annular passage there? between, a comminuted fuel and air inlet member secured to the outer end of said burner member, said inlet member having a tangentially arranged inlet, an annular outlet connected to said second annular passage, and a spiral passage of tapering cross-section connecting said inlet and outlet, and means for axially adjusting said nozzle member to vary the effective discharge area of said second annular passage.

4. A comminuated fuel burner comprising an outer casing adapted to be mounted in a furnace wall opening, a frustro-conical burner member mounted in said outer casing and having its inner port-ion spaced from the walls of said casing to provide an annular passage therebetween, a guide sleeve secured in said burner member, an axially adjustable nozzle member mounted in said guide sleeve and spaced from the inner wall ofsaid burner member to provide a second annular passage therebetween, a comminuted fuel and air inlet member secured to the outer end of said burner member, said inlet member having a tangentially arranged inlet, an annular outlet connected to said second annular passage, 110 and a spiral passage of tapering cross-section connecting said inlet and outlet, regulable means for admitting air for combustion into the interior of said nozzle member, and means for axially adjusting said nozzle mem- 1115 her to vary the efiective discharge area of said second annular passage.

5. A comminuted fuel burner comprising an outer casing adapted to be mounted in a furnace wall opening, a frusto-conical burner no member mounted in said outer casing and having its inner portion spaced from the walls of said casing to provide an annular passage therebetween, angularly spaced openings in said outer casing for admitting air for 125 combustion to said annular passage, a damper sleeve mounted on said casing for regulating the admission of the air, an axially adj ustable nozzle member positioned within said burner member and spaced from the inner 130 'wall thereof to provide a second annular passage therebetween, a comminuted in and aninlet member secured to the outer end of said burner member, said inlet memher having a tangentially arranged inlet an annular outlet connected to said second annular passage, and a spiral passage of tapering cross-section connecting said inlet and outlet, and means for axiall adjustin said 10 nozzle member to vary the e ective disc arge area ofsaid second annular passage.

6. A comminuted fuel burner comprisin in combination a hollow burner member fixe in osition and having a smooth inner surface I an taperin towards its discharge end, means movable re ative to said discharge end for regulating the effective discharge area of said burner member comprising an axially movable nozzle member having a smooth outer 10 surface radially spaced from the inner surface of said burner member and forming an unobstructed annular passage therebetween,

v and means for passing a mixture of air and comminuted fuel in a spiral path to and 85 through said annular pa'mage.

7 comminuted fuel burner comprising a hollow burner member fixed in position and) tapering towards its discharge end, means for passing a combustible mixture of air and I0 comminuted fuel in a iral path to and through said burner mem er comprising an inlet casing of involute form and having an annular discharge outlet opening to said burner member, and means for regulating 86 the linear velocity of said combustible mixture through the discharge end of said burnermember comprising an axially movable nozzle member within said burner member.-

Signed at New York cit in the county of 40 New York and State of Nzaw York, this 3rd day of December, A. D. 1927,

- WALTER F, KEENAN, JR. 

